A wireless local area network (WLAN) is a computer local area network which uses a radio channel as a transmission medium, and is an important supplement and extension to wired networks. In an application scenario of 802.11ah, an access point (AP) can generally support 6000 stations (STAs). 802.11ah is a communications standard for wireless local area networks and is applied to a large number of sensor applications with low power consumption, for example, meter reading, environment monitoring, and smart household. Exemplarily, these STAs may be separately disposed on a water meter, an electricity meter, and a gas meter. The water meter, the electricity meter, and the gas meter may belong to a same company or different companies. By using a wireless AP, these companies can separately send information at a same interval or different intervals to the water meter, the electricity meter, and the gas meter, or update the water meter, the electricity meter, and the gas meter. Therefore, in the application scenario of 802.11ah, an AP can send multicast information at different intervals and of different content to different STAs. Currently, the 802.11ah standard, however, does not define how multicast data is sent to STAs by using a multicast association identifier (AID).